The rest is the result of radioactive decay and the proportions can be used to determine the age of the Earth through radiometric dating. Most of helium in the Earth's crust is a product of alpha decay.
There is a bit of atoms on Earth is at the beginning of its formation does not exist and also not the result of radioactive decay. Carbon-14 is continuously generated by cosmic rays in the atmosphere.
Some atoms on Earth were artificially generated by nuclear reactors or weapons. Of all the transuranium elements numbered atoms greater than 92, only plutonium and neptunium is all there is on Earth naturally. Transuranium elements have radioactive half-life shorter than the age of the Earth, so that these elements have long decay.
Exceptions are the plutonium-244 are likely stored in cosmic dust. Natural content of plutonium and neptunium produced from neutron capture in uranium ore.
Earth contains approximately 1.33 × 1050 atoms. [116] In the planet's atmosphere, there are a small number of atoms of noble gases like argon and neon. The remaining 99% of atoms in the earth's atmosphere in the form of molecules bound, such as carbon dioxide, diatomic oxygen and diatomic nitrogen.
At the Earth's surface, the atoms are bonded together to form various compounds, including water, salt, silicates, and oxides.
Atoms can also be joined to form materials that do not consist of molecules, crystals and metals for example solid or liquid.
